That would make the transition smoother as Rebirth helps reshape our identity towards our ideal-self boosted towards the features the sub (Ascension) works on. Here, water would be the dominant element. Water that adapts and heals.
That would make running Ascension harder yet working deeper towards its goals. Fire is the dominant element here. Fire that purifies and reforges the old into the new.
If you want both of the worlds and a steady, balanced transition into what Ascension offers, then pair it up with CFW. CFW is the perfect balance between fire and water.
LD is more about (sometimes abrupt) breaking out of the old, unfavorable patterns and inspiring you towards forming new, favorable ones, mostly by using fire=purifying and reforging. CFW is more like a balanced alchemical process where you dissolve the old patterns smoothly using fire to reforge or break them and water to ease the reforging process or alleviate the pain of the breaking.
It depends on which element you need more in your alchemical process.
It depends on your goals, but yes, that’s the strongest beast there is. But for people who just want to start their healing journey I would recommend CFW as it’s much less rough and contains a feeling-good component.